CYTOGENETICS AND PROGNOSIS IN CHILDHOOD LYMPHOBLASTIC-LEUKEMIA - RESULTS OF MRC UKALL-X

We have analysed the prognostic influence of cytogenetic findings at d iagnosis in a group of 502 children with acute lymphoblastic leukaemia (ALL), treated on MRC UKALL X, in whom clonal cytogenetic abnormaliti es were detected at diagnosis, Despite the overall improvement in outc ome in children treated on this protocol compared with previous trials , some cytogenetically-defined groups were still associated with a poo r outcome and ploidy retained some prognostic significance, Patients w ith high hyperdiploid ALL (39% of those with clonal abnormalities) had a favourable outcome with event free survival of 71% at 5 years. Thos e with near haploidy (1%), hypodiploidy (9%) and low hyperdiploidy (16 .5%) had a relatively poor prognosis with event-free survival at 5 yea rs of 17%, 42% and 49% respectively, Only two of 12 children with Ph-p ositive leukaemia are alive in remission and abnormalities of chromoso me 11q23 were also associated with a high risk of treatment failure. I n contrast, the t(1;19) was associated with improved event-free surviv al of 87.5% at 5 years. A number of other non-random abnormalities wer e identified with no clear prognostic significance. We conclude that i dentification of certain genetic changes remains important in the mana gement of acute lymphoblastic leukaemia, although whether molecular di agnosis of clinically relevant abnormalities can now supplant cytogene tics in the clinical trials context remains to be determined.